Epilepsy

Epilepsy is characterized by repeated epileptic seizures. In epileptic seizures, the nerve cells in one or both hemispheres of the brain are excessively active. Epileptic seizures occur in very different forms. Sometimes only individual muscles twitch during a seizure, there are sensory disturbances or there are brief periods of absence. In the case of extensive seizures, the entire brain is affected and involuntary movements of the whole body occur with loss of consciousness.

Overview: What is epilepsy?

Epilepsy is a disease of the brain and can have various causes. What all epilepsies have in common is that epileptic seizures occur repeatedly and are triggered by increased brain activity. These seizures usually last no longer than two minutes. Those affected are usually symptom-free between two attacks. However, epileptic seizures can occur without the presence of epilepsy: If external influences trigger an epileptic seizure (e.g. acute illnesses or brain injuries), this is referred to as an occasional seizure. Febrile convulsions in children also often belong to this group.

One speaks of epilepsy when:

• at least two unprovoked epileptic seizures occur more than 24 hours apart, or
• an unprovoked epileptic seizure occurs and there is a high probability that further seizures will occur within the next 10 years.

• Definition according to the International League Against Epilepsy

How does an epileptic seizure occur?

Our brain consists of billions of nerve cells that are networked with each other. During an epileptic seizure, parts of this network become overactive and larger groups of nerve cells release signals simultaneously. This leads to overactivity in the brain. This results in short-term disturbances of behavior or consciousness, e.g. sensory disturbances, involuntary movements or unconsciousness.

Epilepsy: causes and risk factors

There are various causes of epilepsy:

• Injuries to the brain
• Genetic predisposition
• Prenatal brain damage
• Brain malformations
• Stroke
• Brain tumor
• Metabolic diseases
• Meningitis or inflammation of the brain
• Autoimmune encephalitis

Often, however, there is no visible or clear cause for the epilepsy.

According to these causes, the most common types of epilepsy are

• Structural epilepsy (also known as symptomatic epilepsy): In structural epilepsy, a disease or brain change or brain damage is responsible for the epilepsy. The seizures are usually triggered by a limited area in the brain (focal seizures).
• Genetic epilepsy (also known as idiopathic epilepsy): The cause of epilepsy is a suspected or proven genetic predisposition. The seizures often affect both hemispheres of the brain at the same time (generalized seizures).
• Epilepsy with an unknown cause (also known as cryptogenic epilepsy): In this case, no cause for the epilepsy can be found.

Risk factors for epileptic seizures

If epilepsy is compared to a “thunderstorm in the brain”, then epileptic seizures are the “lightning strikes”. The exact time or location of an epileptic seizure, as with a lightning strike, cannot be accurately predicted. This uncertainty can be stressful for those affected. As with a weather forecast, the previous seizure calendar, the EEG (brain wave curve) and brain imaging help doctors to assess the risk of seizures.

Certain factors can promote seizures in people with epilepsy.

Typical examples are

• Lack of sleep
• High physical or mental stress
• High fever
• Certain medications
• Withdrawal from alcohol, drugs or sleeping pills
• Flickering light for some people

Symptoms: Epilepsy and seizure types

The most important symptom of epilepsy is epileptic seizures. These occur when groups of nerve cells in the brain suddenly discharge simultaneously. Seizures can look different. Typical signs of a seizure are empty, open, staring or twisted eyes. Other symptoms include impaired consciousness, falls, twitching and involuntary movements.

The symptoms that occur during an epileptic seizure depend on this,

• how many nerve cells discharge at once,
• which area of the brain is affected and
• whether the discharges are spreading.

What happens during an epileptic seizure?

In some people, the seizure only lasts a few seconds. This brief absence can occur up to 100 times a day. Others may only experience altered sensory perception, loss of taste, sensation or vision. Those affected are often unresponsive during epileptic seizures, even though they have their eyes open. They may have a blank stare, smack their lips or make nodding movements with their hands.

In more severe forms of seizures, individual extremities, such as an arm or a leg, twitch. Still other people with epilepsy have seizures that cause twitching all over the body. Doctors then speak of a generalized tonic-clonic seizure.

An epileptic seizure usually lasts no longer than two to three minutes and in the vast majority of cases stops on its own. Rarely does a single epileptic seizure last longer. From a duration of five minutes or more, doctors speak of a “status epilepticus”. This is an emergency and must be treated quickly with medication.

After a stressful epileptic seizure, those affected are often very exhausted and sleep a lot. Other temporary symptoms (“postictal symptoms”) after a seizure include memory problems, depressive moods or speech disorders. However, many sufferers feel well again after just a few minutes and have no further complaints.

Forms of seizure

• Absence: Short seizures, typically in childhood, which are associated with a clouding of consciousness. Those affected seem to be lost in a “daydream” and do not react to being spoken to.
• Myoclonic seizure: Seizures associated with twitching of individual muscle groups in quick succession. Those affected remain conscious.
• Focal seizures: In a focal epileptic seizure, limited areas of the brain are affected. The first sign of a focal seizure can be a so-called aura. The aura is accompanied by an altered perception. For example, smelling or tasting is altered. Dizziness, hallucinations or anxiety can also be part of an aura. A variety of symptoms can occur in the further course of focal seizures. The most common symptoms are paresthesia, automated movements, twitching, speech disorders, fixed gaze, clouding of consciousness, etc. Focal seizures can develop into generalized seizures (secondary generalization).
• Generalized tonic-clonic seizure: In a generalized tonic-clonic epileptic seizure (also known as a grand mal seizure), both hemispheres of the brain are affected by the seizure. This results in unconsciousness and twitching and cramping of the extremities. Those affected can bite their tongue, wet themselves and injure themselves by falling.

Epilepsy: Diagnosis with us

A single seizure does not mean that it is actually epilepsy. Because seizures can also have other causes. Your general practitioner will refer you to the neurology department if epilepsy is suspected. They will first clarify whether the symptoms were actually an epileptic seizure and you will be asked various questions:

• Were there specific triggers for the seizure?
• Did the seizure announce itself in advance?
• What symptoms occurred during the seizure?
• How long did the seizure last?
• What were the symptoms after the seizure?
• Have you had similar seizures in the past?

Those affected often have little or no memory of their seizure. Information from outsiders who have observed the seizure is then helpful. In such situations, video recordings of the seizure (e.g. with a smartphone) are extremely useful in arriving at the correct diagnosis. If a diagnosis of epilepsy is likely, the doctor will arrange for further examinations.

Procedure for the diagnosis of epilepsy

After the initial consultation, we will give you a thorough physical examination. Important additional diagnostic procedures are:

• Electroencephalogram (EEG): We use an EEG to measure brain waves. These are visualized on a monitor in the form of waves. Based on characteristic patterns, we can recognize whether affected persons are prone to epileptic seizures. The examination is initially carried out over 20 minutes. In unclear cases, however, it is sometimes necessary to carry out longer drains over several days.
• 
  Magnetic resonance imaging (MRI)
  An MRI helps us to find out whether certain changes in the brain trigger the seizures. We can also compare the size and composition of brain regions with each other in order to recognize even slight changes.
• 
  Computed tomography (CT
  ): Like an MRI, a CT scan is used to detect changes in the brain.
• 
  Positron emission tomography
  mission tomography (PET): PET can be used to detect reduced glucose metabolism in certain areas affected by epilepsy during the seizure-free interval.
• Laboratory tests: After a seizure, certain blood values are elevated for several hours. A blood count can also provide information about the cause of the epilepsy. If necessary, we will examine the cerebrospinal fluid (CSF).
• Genetic testing: if a genetic predisposition or metabolic disorder is suspected, genetic testing can be arranged.

Further examinations may be necessary to rule out other causes behind the epilepsy.

Is it really epilepsy?

Many other diseases lead to symptoms that can resemble epileptic seizures. Distinguishing between the possible causes of these complaints is often not easy. Specialists from all areas of medicine are represented at the USZ who can clarify these causes. In order to make the correct diagnosis, it is often necessary for many disciplines to work together.

Diseases that may resemble epileptic seizures:

• Brain strokes and strokes: a short-term circulatory disorder in parts of the brain can lead to paralysis, speech disorders or sensory disturbances. This is a medical emergency and must be clarified and treated quickly. Specialists for such diseases are available day and night at the Stroke Unit of the USZ.
• Syncope: If the blood supply to both hemispheres of the brain is briefly interrupted, those affected may faint. Fainting spells can be triggered by certain situations (getting up quickly from a lying position, hot and stuffy rooms). However, heart disease may also be present. Colleagues in cardiology clarify such diseases of the heart.
• Functional seizures: Psychological factors play an important role in many diseases. In some cases, purely mental illnesses can lead to loss of consciousness or involuntary movements. The Clinic for Consultative Psychiatry and Psychosomatics treats mental illnesses at the USZ.
• Movement disorders: Involuntary movements do not only occur during epileptic seizures. Specialists in movement disorders not only treat Parkinson’s disease at the USZ, but also other disorders such as tremor, dystonia and tics.
• Dizziness: The cause of falls and dizziness can lie in the balance system. Our colleagues at the Vertigo Centre specialize in the assessment and treatment of such disorders.

Epilepsy: prevention, early detection, prognosis

Anyone who has had an epileptic seizure once will not necessarily have a second one. Only when the seizures recur does the likelihood of further seizures increase. Epileptic seizures can be prevented with medication. Long-term freedom from seizures can be achieved in more than two thirds of cases. It is also advisable to adapt your lifestyle if you have been diagnosed with epilepsy. These include, for example, a regular sleep pattern, sufficient rest and a reduction in alcohol consumption. There is no early detection test for epilepsy.

Progression and prognosis of epilepsy

How severe epilepsy is and how often seizures occur varies from person to person. In many cases, long-term treatment is necessary. How the disease progresses depends, among other things, on what triggered the epilepsy and how well the treatment works. In certain cases, epilepsy can also pass again. This is more common in certain forms of childhood epilepsy. Epilepsy is considered to have been overcome if those affected have remained seizure-free for at least ten years and have not taken anti-epileptic drugs for at least five years.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Epilepsy: treatment with antiepileptic drugs

A single epileptic seizure does not necessarily need to be treated if there is no evidence of an increased risk of further seizures. In the case of very rare or very mild seizures, we carefully consider whether and which therapy is suitable.

Most patients with epilepsy take long-term medication – so-called antiepileptic drugs – to prevent seizures. With such medication, more than two thirds of epilepsy patients can achieve freedom from seizures. If drug therapy does not achieve the desired success, there are other treatment options.

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